JSON configuration alternative in Terraform - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Configuration

intermediate

Identify the correct JSON equivalent of a Terraform resource block

Given the following Terraform HCL resource block, which JSON configuration correctly represents it?

resource "aws_s3_bucket" "example" {
  bucket = "my-bucket"
  acl    = "private"
}

A

{
  "resource": {
    "aws_s3_bucket": {
      "example": {
        "bucket": "my-bucket",
        "acl": "private"
      }
    }
  }
}

B

{
  "aws_s3_bucket": {
    "example": {
      "bucket": "my-bucket",
      "acl": "private"
    }
  }
}

C

{
  "resource": {
    "aws_s3_bucket": {
      "example": [
        {
          "bucket": "my-bucket",
          "acl": "private"
        }
      ]
    }
  }
}

D

{
  "resource": {
    "aws_s3_bucket": {
      "example": {
        "name": "my-bucket",
        "access_control": "private"
      }
    }
  }
}

💡 Hint

Remember that Terraform JSON uses nested objects under "resource" with resource type and name keys.

Terraform JSON configuration requires a top-level "resource" key, then resource type, then resource name as nested objects. The properties must match the HCL keys exactly.

❓ service_behavior

intermediate

What happens if a required attribute is missing in Terraform JSON config?

If you omit a required attribute like "bucket" in the JSON configuration for an aws_s3_bucket resource, what will Terraform do when you run apply?

A Terraform will create the resource but with empty or null values for missing attributes.

B Terraform will throw a validation error and refuse to apply the configuration.

C Terraform will apply the configuration successfully with default values for missing attributes.

D Terraform will ignore the resource block entirely and continue with other resources.

💡 Hint

Think about how Terraform validates required fields before creating resources.

Terraform validates required attributes before applying. Missing required attributes cause errors and prevent apply.

❓ Architecture

advanced

How to represent multiple resources in Terraform JSON configuration?

You want to define two aws_s3_bucket resources named "bucket1" and "bucket2" in Terraform JSON. Which JSON snippet correctly represents this?

A

{
  "resource": {
    "aws_s3_bucket": {
      "bucket1": {"bucket": "bucket-one", "acl": "private"},
      "bucket2": {"bucket": "bucket-two", "acl": "public-read"}
    }
  }
}

B

{
  "resource": [
    {"aws_s3_bucket": {"bucket1": {"bucket": "bucket-one", "acl": "private"}}},
    {"aws_s3_bucket": {"bucket2": {"bucket": "bucket-two", "acl": "public-read"}}}
  ]
}

C

{
  "resource": {
    "aws_s3_bucket": [
      {"bucket1": {"bucket": "bucket-one", "acl": "private"}},
      {"bucket2": {"bucket": "bucket-two", "acl": "public-read"}}
    ]
  }
}

D

{
  "resource": {
    "aws_s3_bucket": {
      "bucket1": {"bucket": "bucket-one", "acl": "private"}
    },
    "aws_s3_bucket": {
      "bucket2": {"bucket": "bucket-two", "acl": "public-read"}
    }
  }
}

💡 Hint

Remember JSON keys must be unique; multiple resources of the same type are nested under the same resource type key.

Terraform JSON groups multiple resources of the same type under one resource type key with unique resource names as keys.

❓ security

advanced

How to securely manage sensitive variables in Terraform JSON configuration?

You have a sensitive variable like a database password. Which approach is best to avoid exposing it directly in Terraform JSON configuration files?

A Encrypt the password manually and store the encrypted string in the JSON configuration.

B Store the password in a separate JSON file in the same directory and import it.

C Use environment variables or Terraform Cloud workspace variables and reference them in JSON without hardcoding.

D Hardcode the password directly in the JSON configuration under a variable block.

💡 Hint

Think about how Terraform handles sensitive data securely without exposing it in config files.

Terraform recommends using environment variables or remote workspace variables to keep sensitive data out of config files.

🧠 Conceptual

expert

What is the main difference between Terraform HCL and JSON configuration formats?

Which statement best describes the key difference between Terraform's HCL and JSON configuration formats?

A JSON supports dynamic expressions and functions, while HCL does not.

B JSON configuration files are only used for Terraform Cloud and not for local Terraform runs.

C HCL configurations cannot be converted to JSON format.

D HCL supports comments and more readable syntax, while JSON does not support comments and is more verbose.

💡 Hint

Consider readability and syntax features of both formats.

HCL is designed for humans with comments and simpler syntax. JSON is strict, no comments, and more verbose.

Practice

1. What is the main reason to use JSON configuration files in Terraform instead of the usual HCL language?

easy

A. To enable automation and integration with other tools

B. Because JSON files are easier to read for humans

C. To reduce the size of the configuration files

D. Because Terraform does not support HCL anymore

Solution

1. Step 1: Understand Terraform configuration formats

   Terraform supports both HCL and JSON formats for configuration files.

2. Step 2: Identify the benefit of JSON format

   JSON is often used for automation and integration with other tools because it is a widely supported data format.

3. Final Answer:

   To enable automation and integration with other tools -> Option A

4. Quick Check:

   JSON helps automation = C [OK]

Hint: JSON is best for automation and tool integration [OK]

Common Mistakes:

• Thinking JSON is easier for humans to read than HCL
• Believing Terraform no longer supports HCL
• Assuming JSON reduces file size

2. Which of the following is the correct way to start a Terraform JSON configuration file?

easy

A. { "resource": { "aws_instance": { "example": { "ami": "ami-123456", "instance_type": "t2.micro" } } } }

B. { resource: { aws_instance: { example: { ami: "ami-123456", instance_type: "t2.micro" } } } }

C. { "resource": [ { "aws_instance": { "example": { "ami": "ami-123456", "instance_type": "t2.micro" } } } ] }

D. [ "resource": { "aws_instance": { "example": { "ami": "ami-123456", "instance_type": "t2.micro" } } } ]

Solution

1. Step 1: Check JSON syntax rules

   JSON keys and strings must be in double quotes, and objects use curly braces {}.

2. Step 2: Identify correct Terraform JSON structure

   Terraform expects "resource" as a key with nested objects, not arrays or unquoted keys.

3. Final Answer:

   { "resource": { "aws_instance": { "example": { "ami": "ami-123456", "instance_type": "t2.micro" } } } } -> Option A

4. Quick Check:

   Proper JSON syntax with quoted keys = A [OK]

Hint: Always use double quotes for keys and strings in JSON [OK]

Common Mistakes:

• Using unquoted keys in JSON
• Using arrays instead of objects for resources
• Mixing JSON and HCL syntax

3. Given this Terraform JSON snippet:

{
  "variable": {
    "region": {
      "default": "us-west-2"
    }
  },
  "provider": {
    "aws": {
      "region": "${var.region}"
    }
  }
}

What will happen when you run terraform apply?

medium

A. Terraform will deploy resources in the us-west-2 region

B. Terraform will throw an error because variable interpolation is not supported in JSON

C. Terraform will ignore the provider region and use the default AWS region

D. Terraform will deploy resources but with an empty region value

Solution

1. Step 1: Understand variable interpolation in Terraform JSON

   Terraform JSON does not support interpolation syntax like "${var.region}" inside JSON files.

2. Step 2: Identify the error cause

   Using interpolation in JSON causes Terraform to fail parsing or applying the configuration.

3. Final Answer:

   Terraform will throw an error because variable interpolation is not supported in JSON -> Option B

4. Quick Check:

   Interpolation not allowed in JSON = A [OK]

Hint: No interpolation syntax allowed in Terraform JSON files [OK]

Common Mistakes:

• Assuming interpolation works same as HCL
• Thinking Terraform ignores invalid region values
• Believing Terraform defaults region silently

4. You have this JSON Terraform config snippet:

{
  "resource": {
    "aws_instance": {
      "ami": "ami-123456",
      "instance_type": "t2.micro",
      "tags": {
        "Name": "ExampleInstance"
      }
    }
  }
}

When running terraform apply, you get a syntax error. What is the most likely cause?

medium

A. The JSON keys are not properly quoted

B. The "tags" block should be an array, not an object

C. The JSON file is missing a root-level "terraform" key

D. The JSON file uses incorrect nesting for resource blocks

Solution

1. Step 1: Review Terraform JSON resource structure

   Terraform expects resource blocks nested as: resource type -> resource name -> attributes.

2. Step 2: Check the nesting in the snippet

   The snippet places attributes directly under the resource type "aws_instance" without the required instance name (e.g., "example") as an intermediate object key.

3. Final Answer:

   The JSON file uses incorrect nesting for resource blocks -> Option D

4. Quick Check:

   Resource nesting must follow Terraform JSON schema = B [OK]

Hint: Check resource nesting carefully in JSON configs [OK]

Common Mistakes:

• Confusing JSON object vs array for tags
• Expecting a "terraform" root key in JSON
• Not quoting JSON keys properly

5. You want to convert this HCL Terraform config to JSON:

resource "aws_s3_bucket" "bucket" {
  bucket = "my-bucket"
  acl    = "private"
  tags = {
    Environment = "Dev"
    Team        = "Cloud"
  }
}

Which JSON configuration correctly represents this resource?

hard

A. {
"resource": {
"aws_s3_bucket": {
"bucket": "my-bucket",
"acl": "private",
"tags": {
"Environment": "Dev",
"Team": "Cloud"
}
}
}
}

B. {
"resource": [
{
"aws_s3_bucket": {
"bucket": {
"bucket": "my-bucket",
"acl": "private",
"tags": {
"Environment": "Dev",
"Team": "Cloud"
}
}
}
}
]
}

C. {
"resource": {
"aws_s3_bucket": {
"bucket": {
"bucket": "my-bucket",
"acl": "private",
"tags": {
"Environment": "Dev",
"Team": "Cloud"
}
}
}
}
}

D. {
"resources": {
"aws_s3_bucket": {
"bucket": {
"bucket": "my-bucket",
"acl": "private",
"tags": {
"Environment": "Dev",
"Team": "Cloud"
}
}
}
}
}

Solution

1. Step 1: Understand Terraform JSON resource format

   Terraform JSON uses "resource" (singular) as the root key with nested resource type and name.

2. Step 2: Compare options for correct keys and structure

   { "resource": { "aws_s3_bucket": { "bucket": { "bucket": "my-bucket", "acl": "private", "tags": { "Environment": "Dev", "Team": "Cloud" } } } } } correctly uses "resource" with nested "aws_s3_bucket" and resource name "bucket" with attributes.

3. Final Answer:

   { "resource": { "aws_s3_bucket": { "bucket": { "bucket": "my-bucket", "acl": "private", "tags": { "Environment": "Dev", "Team": "Cloud" } } } } } -> Option C

4. Quick Check:

   Correct root key and nesting = D [OK]

Hint: Use singular "resource" key with nested type and name [OK]

Common Mistakes:

• Using "resources" instead of "resource"
• Using arrays instead of objects for resources
• Incorrect nesting of resource name and attributes